The Plant Clinic has had reports of the fungal disease pachysandra, the popular shade ground cover. Kentucky has been experiencing this disease for two weeks, and reports have come from the southern part of Illinois as well. I usually see this disease in my Champaign garden, but that has not yet happened. Keep an eye out for this disease soon, particularly if wet conditions persist in your area.
The disease may begin as brown blotches on leaves, but it progresses through stems and stolons, causing cankers that girdle and kill the stems. Look for wilted pachysandra plants with brown blotches on the leaves. Push back the leaves to find the blotches and cankers on stems. One diagnostic feature to look for is pink-to-orange spore masses on the underside of leaves or on stems. Look particularly for Volutella blight in dense plantings where heavy mulch has been used and where conditions are warm and moist. The disease often follows some type of stress, such as winter injury, insect infestation, sun scald, or recent shearing. Remove and destroy any severely infected plants—when plants are dry, if you can wait.
Chemicals may be used as protectants; repeat applications are necessary at 10- to 14-day intervals, depending on the product and weather conditions. Chlorothalonil, copper fungicides, Duosan, Fore, mancozeb, and Zyban are registered for this use on pachysandra. If you have had problems with this disease in the past, consider chemical applications now. Effective nonchemical controls include keeping insects under control and mulching pachysandra with a material that does not hold moisture. Pruning any surrounding plants for better air movement in the area may also help manage this fungus. Consult Report on Plant Disease No. 649 for more information.